1. Implementation of a Functional Programming Language
Jason Koenig
Computer Systems Lab
TJHSST

2. Introduction Creation of a functional language
Both design and implementation
Working
Parsing
Optimization
Execution
Todo: Multiple Files, I/O

3. What is a Functional Language?
Two approaches:
Imperative – like a recipe, or a how to.
Declarative – like a mathematical formula.
Functions are first class citizens
Functions are like data

4. Design
Goals
Small and lightweight
Core language highly portable
Other functionality in standard library
Easily embedded in other programs as scripting language
Driven by implementation, rather than some external metric

5. Implementation File, Input Optimizer Executor Parser Program Output
Characters
Optimized Code Tree
Lexical
Analysis
Syntax Tree
Executor
Tokens
Bytes
Parser
Program
Output

6. Sample Programs let even = {x| if x == 1 then false else odd.x-1},
odd = {x| if x == 1 then true else even.x-1} in
(even.2000)

7. Sample Program let even = {x| if x == 1 then false else odd.x-1},
odd = {x| if x == 1 then true else even.x-1} in
(even.2000)

8. Sample Program let compose = {f, g, x | f.(g.x)}, add2 = {a| a+2},
mult3 = {a| a*3},
mult3add6 = compose.mult3.add2 in
mult3add6.5

9. Future Work Tail Recursion G-machine compilation of functions Language
Imperative style constructs
Standard Library
Implementation: C for speed